Human immunodeficiency virus (HIV) affects more than on million people in the United States today. Because no effective cure or vaccination is imminent, the most effective measure available to fight the spread of AIDS is public education. However, development of effective prevention programs requires and understanding of the mechanisms underlying high-risk behaviors. We propose to examine the role of alcohol sue as a factor contributing to high-risk sexual behavior among adolescents (a group at elevated risk for AIDS) and to investigate factors promoting alcohol use in social situations likely to lead to sexual encounters. A theoretical model is presented that links alcohol use in social and sexual situations to increased likelihood of engaging in high-risk sexual behaviors. Hypothetically, adolescents drink in social/sexual situations either to cope with negative emotion or to enhance positive emotion. In turn, drinking for coping and enhancement motive are hypothesized to reflect different underlying etiologic processes. Preliminary studies conducted with college and adult community samples support key aspects of the model. A cross-sectional survey is proposed to investigate alcohol use in relation to high-risk sexual behaviors in a stratified (race and sex) random sample of 2000 adolescents in Buffalo, NY. Face-to- face interviews will be conducted in a central site by trained same-sex interviewers. A situation-specific measurement strategy is proposed in which the following key constructs are assessed: (1) high-risk sexual behaviors, (2) alcohol use in social/sexual situation, (3) drinking motives and alcohol expectancies, (4) perceived threat in social/sexual situations, and (5) psychosocial and personality variables theoretically related to perceived threat in social and sexual situations. The proposed research has important implications for understanding the contributions of alcohol use in social and sexual situations to subsequent high-risk sexual behaviors, and for elucidating the determinants of drinking in the situations. To the extent that high-risk sexual behaviors are promoted by alcohol use in social and sexual situations, and understanding of processes underlying drinking in these situations will provide and important basis for developing specific and focused intervention strategies. The emphasis on distinguishing motives for drinking in these situations may lead to the development of programs targeted for specific high- risk subgroups for whom effective behavior change strategies may differ.